This invention relates to ball type check valves of simple rugged construction offering dependable operation and durability even under severe high pressure service conditions. The valves of this invention are outstanding in their resistance to fatigue cracking and related structural failures when used in systems exposed to the stresses of cyclic pressure variations, such as are generated by reciprocating compressors, plunger type intensifier pumps and the like.
Ball type check valves are widely employed in order to stop the back flow of fluids in a wide variety of devices and systems. However, none of the multitude of individual designs which have previously been devised has provided satisfactory service life under exposure to severe stress cycles from repeated sharp pressure fluctuations. Such repeated stress cycles can cause fatigue cracks to develop at any point or area of weakness. However, most such failures occur at or near various edges of other sharply defined changes in geometrical shape or surface, such as threaded segments and recessed seats or stepped shoulder portions, particularly within the valve body proper and associated parts which are directly exposed to full fluid pressure
The primary object of the present invention is to provide a simple ball stop check valve which performs reliably in high pressure fluids service with exceptional structural longevity and freedom from fatigue failures. A related object is to compose the valve from a limited number of primary component parts having simple compact shapes which can be readily fabricated with all inner surfaces, seats and sealing areas readily accessible for finishing to high pressure stress resistant condition.
Another object is to reduce maintenance costs by providing a check valve which is not only durable in high pressure fluid systems but which is also assembled in a direct, positive and easy manner so as to assure convenient access to all parts for economical servicing.
Still other objects and advantages of the invention will become apparent from the following details thereof.